Divergent transcriptional responses to low temperature among populations of alpine and lowland species of New Zealand stick insects (Micrarchus).

In widespread and genetically structured populations, temperature variation may lead to among-population differentiation of thermal biology. The New Zealand stick insect genus Micrarchus contains four species that inhabit different thermal environments, two of which are geographically widespread. RNA-Seq and quantitative PCR were used to investigate the transcriptional responses to cold shock among lowland and alpine species to identify cold-responsive transcripts that differ between the species and to determine whether there is intraspecific geographical variation in gene expression. We also used mitochondrial DNA, nuclear 28S ribosomal DNA and transcriptome-wide SNPs to determine phylogeographic structure and the potential for differences in genetic backgrounds to contribute to variation in gene expression. RNA-Seq identified 2160 unigenes that were differentially expressed as a result of low-temperature exposure across three populations from two species (M. hystriculeus and M. nov. sp. 2), with a majority (68% ± 20%) being population specific. This extensive geographical variation is consistent across years and is likely a result of background genetic differences among populations caused by genetic drift and possibly local adaptation. Responses to cold shock shared among alpine M. nov. sp. 2 populations included the enrichment of cuticular structure-associated transcripts, suggesting that cuticle modification may have accompanied colonization of low-temperature alpine environments and the development of a more cold-hardy phenotype

Overwintering in New Zealand stick insects

Stick insects are found in a variety of habitats throughout New Zealand, including at least four species that occur at high altitudes. Here they face physiological challenges that differ from their typically warmer lowland habitats, but their strategies to deal with harsh winter conditions are not known. Autumn and winter field surveys, coupled with caging experiments, were conducted to determine which life stages are overwintering in montane and lowland habitats. Data loggers were placed for approximately one year at each site to measure the leaf litter and canopy microhabitat temperatures. From this, we have found that alpine and lowland stick insects persist in a variety of life stages throughout the year despite multiple exposure to freezing temperatures

Identification of cold-responsive genes in a New Zealand alpine stick insect using RNA-Seq.

The endemic New Zealand alpine stick insect Micrarchus nov. sp. 2 regularly experiences sub-zero temperatures in the wild. 454-based RNA-Seq was used to generate a de novo transcriptome and differentiate between treatments to investigate the genetic basis of cold tolerance. Non cold-treated individuals were compared to those exposed to 0°C for 1 h followed by a 1 h recovery period at 20°C. We aligned 607,410 Roche 454 reads, generating a transcriptome of 5235 contigs. Differential expression analysis ranked candidate cold responsive genes for qPCR validation by P-value. The top nine up-regulated candidates, together with eight a priori targets identified from previous studies, had their relative expression quantified using qPCR. Three candidate cold responsive genes from the RNA-Seq data were verified as significantly up-regulated, annotated as: prolyl 4-hydroxylase subunit alpha-1 (P4HA1), staphylococcal nuclease domain-containing protein 1 (snd1) and cuticular protein analogous to peritrophins 3-D2 (Cpap3-d2). All three are novel candidate genes, illustrating the varied response to low temperature across insects

Predicting how many animals will be where: how to build, calibrate and evaluate individual-based models

Individual-based models (IBMs) can simulate the actions of individual animals as they interact with one another and the landscape in which they live. When used in spatially-explicit landscapes IBMs can show how populations change over time in response to management actions. For instance, IBMs are being used to design strategies of conservation and of the exploitation of fisheries, and for assessing the effects on populations of major construction projects and of novel agricultural chemicals. In such real world contexts, it becomes especially important to build IBMs in a principled fashion, and to approach calibration and evaluation systematically. We argue that insights from physiological and behavioural ecology offer a recipe for building realistic models, and that Approximate Bayesian Computation (ABC) is a promising technique for the calibration and evaluation of IBMs. IBMs are constructed primarily from knowledge about individuals. In ecological applications the relevant knowledge is found in physiological and behavioural ecology, and we approach these from an evolutionary perspective by taking into account how physiological and behavioural processes contribute to life histories, and how those life histories evolve. Evolutionary life history theory shows that, other things being equal, organisms should grow to sexual maturity as fast as possible, and then reproduce as fast as possible, while minimising per capita death rate. Physiological and behavioural ecology are largely built on these principles together with the laws of conservation of matter and energy. To complete construction of an IBM information is also needed on the effects of competitors, conspecifics and food scarcity; the maximum rates of ingestion, growth and reproduction, and life-history parameters. Using this knowledge about physiological and behavioural processes provides a principled way to build IBMs, but model parameters vary between species and are often difficult to measure. A common solution is to manually compare model outputs with observations from real landscapes and so to obtain parameters which produce acceptable fits of model to data. However, this procedure can be convoluted and lead to over-calibrated and thus inflexible models. Many formal statistical techniques are unsuitable for use with IBMs, but we argue that ABC offers a potential way forward. It can be used to calibrate and compare complex stochastic models and to assess the uncertainty in their predictions. We describe methods used to implement ABC in an accessible way and illustrate them with examples and discussion of recent studies. Although much progress has been made, theoretical issues remain, and some of these are outlined and discussed

Characterising differences between self-reported and wastewater-identified drug use at two consecutive years of an Australian music festival.

BackgroundIn the context of drug prohibition, potential adulteration and variable purity pose additional health risks for people who use drugs, with these risks often compounded by the outdoor music festival environment. Ahead of the imminent implementation of drug checking services in Queensland, Australia, this study aims to characterise this problem using triangulated survey and wastewater data to understand self-reported and detected drug use among attendees of a multi-day Queensland-based music festival in 2021 and 2022.MethodsWe administered an in-situ survey focusing on drug use at the festival to two convenience samples of 136 and 140 festival attendees in 2021 and 2022 respectively. We compared survey findings to wastewater collected concurrently from the festival's site-specific wastewater treatment plant, which was analysed using Liquid Chromatography Tandem Mass Spectrometry.ResultsMost survey respondents (82 % in 2021, 92 % in 2022) reported using or intending to use an illicit drug at the festival. Some respondents reported potentially risky drug use practices such as using drugs found on the ground (2 % in 2021, 4 % in 2022). Substances detected in wastewater but not surveys include MDEA, mephedrone, methylone, 3-MMC, alpha-D2PV, etizolam, eutylone, and N,N-dimethylpentylone.ConclusionMany substances detected in wastewater but not self-reported in surveys likely represent substitutions or adulterants. These findings highlight the benefits of drug checking services to prevent harms from adulterants and provide education on safer drug use practices. These findings also provide useful information on socio-demographic characteristics and drug use patterns of potential users of Queensland's future drug checking service

Parkinson's disease: neurological manifestations and possibilities for neurosurgery

Parkinson's disease is caused by the progressive degeneration of nerve cells that produce dopamine, a neurotransmitter essential for motor coordination. The most common symptoms of Parkinson's disease are resting tremors, muscle rigidity, slow voluntary movements and postural instability. Furthermore, the disease can cause cognitive, emotional, sensory and autonomic changes. There are two main types of neurosurgery for Parkinson's disease: ablative surgery and deep brain stimulation (DBS). Objective: to evaluate the impact of neurosurgery for Parkinson's disease in improving motor symptoms, reducing medication side effects, preserving cognitive functions and improving patients' quality of life. Methodology: followed the PRISMA checklist. The databases used were PubMed, Scielo, Web of Science and Google Scholar. The descriptors used were: “Parkinson's disease”, “neurosurgery”, “ablation”, “deep brain stimulation” and “outcome”. The inclusion criteria were: articles that compared the two types of neurosurgery for Parkinson's disease (ablative surgery and deep brain stimulation), that evaluated clinical outcomes (motor symptoms, medication side effects, cognitive functions and quality of life) and that used standardized scales to measure these outcomes. The exclusion criteria were: articles that did not compare the two types of neurosurgery for Parkinson's disease, that did not evaluate the clinical outcomes of interest, that used non-validated or inadequate scales to measure these outcomes. Results: 15 studies were selected. Both types of neurosurgery for Parkinson's disease have been effective in improving patients' motor symptoms, especially tremors, rigidity, and bradykinesia. However, deep brain stimulation had an advantage over ablative surgery in terms of reducing medication side effects, such as motor fluctuations and dyskinesias. Deep brain stimulation was also safer and less invasive than ablative surgery, presenting fewer complications such as hemorrhage, infection, neurological deficits, and cognitive or psychiatric changes. However, deep brain stimulation showed greater improvement than ablative surgery, especially in physical, emotional and social aspects of quality of life. Conclusion: neurosurgery for Parkinson's disease is a valid therapeutic option for patients who do not respond adequately to drug treatment or who have intolerable side effects. Among the two main types of neurosurgery for Parkinson's disease, deep brain stimulation appears to be superior to ablative surgery in terms of efficacy, safety, and impact on patients' quality of life.Parkinson's disease is caused by the progressive degeneration of nerve cells that produce dopamine, a neurotransmitter essential for motor coordination. The most common symptoms of Parkinson's disease are resting tremors, muscle rigidity, slow voluntary movements and postural instability. Furthermore, the disease can cause cognitive, emotional, sensory and autonomic changes. There are two main types of neurosurgery for Parkinson's disease: ablative surgery and deep brain stimulation (DBS). Objective: to evaluate the impact of neurosurgery for Parkinson's disease in improving motor symptoms, reducing medication side effects, preserving cognitive functions and improving patients' quality of life. Methodology: followed the PRISMA checklist. The databases used were PubMed, Scielo, Web of Science and Google Scholar. The descriptors used were: “Parkinson's disease”, “neurosurgery”, “ablation”, “deep brain stimulation” and “outcome”. The inclusion criteria were: articles that compared the two types of neurosurgery for Parkinson's disease (ablative surgery and deep brain stimulation), that evaluated clinical outcomes (motor symptoms, medication side effects, cognitive functions and quality of life) and that used standardized scales to measure these outcomes. The exclusion criteria were: articles that did not compare the two types of neurosurgery for Parkinson's disease, that did not evaluate the clinical outcomes of interest, that used non-validated or inadequate scales to measure these outcomes. Results: 15 studies were selected. Both types of neurosurgery for Parkinson's disease have been effective in improving patients' motor symptoms, especially tremors, rigidity, and bradykinesia. However, deep brain stimulation had an advantage over ablative surgery in terms of reducing medication side effects, such as motor fluctuations and dyskinesias. Deep brain stimulation was also safer and less invasive than ablative surgery, presenting fewer complications such as hemorrhage, infection, neurological deficits, and cognitive or psychiatric changes. However, deep brain stimulation showed greater improvement than ablative surgery, especially in physical, emotional and social aspects of quality of life. Conclusion: neurosurgery for Parkinson's disease is a valid therapeutic option for patients who do not respond adequately to drug treatment or who have intolerable side effects. Among the two main types of neurosurgery for Parkinson's disease, deep brain stimulation appears to be superior to ablative surgery in terms of efficacy, safety, and impact on patients' quality of life

Interactions between Predation and Resources Shape Zooplankton Population Dynamics

Identifying the relative importance of predation and resources in population dynamics has a long tradition in ecology, while interactions between them have been studied less intensively. In order to disentangle the effects of predation by juvenile fish, algal resource availability and their interactive effects on zooplankton population dynamics, we conducted an enclosure experiment where zooplankton were exposed to a gradient of predation of roach (Rutilus rutilus) at different algal concentrations. We show that zooplankton populations collapse under high predation pressure irrespective of resource availability, confirming that juvenile fish are able to severely reduce zooplankton prey when occurring in high densities. At lower predation pressure, however, the effect of predation depended on algal resource availability since high algal resource supply buffered against predation. Hence, we suggest that interactions between mass-hatching of fish, and the strong fluctuations in algal resources in spring have the potential to regulate zooplankton population dynamics. In a broader perspective, increasing spring temperatures due to global warming will most likely affect the timing of these processes and have consequences for the spring and summer zooplankton dynamics